While not difficult to build a basic version, at-scale incident alert & escalation systems are a mix of all the things that engineers hate building for (timezon

While not difficult to build a basic version, at-scale incident alert & escalation systems are a mix of all the things that engineers hate building for (timezones, calendars, telephones, human-injected overrides, contact management, and 3rd party notification / acknowledgement tracking) all wrapped into a system that's being watched and scrutinized by everyone from compliance, legal and eng all the way to the CEO when they're at their most emotional during and after an incident. IME for most companies it only takes a homegrown system failing once during a major outage for the budget to open up.